The invention relates to an under floor air cooled housing system, for aircraft electrical devices for passenger use such as passenger seat electronics units (SEU) or digital system entertainment boxes, in particular a housing system for retrofit relocation of existing devices from under passenger seats to an air cooled protective under floor housing for improved duty life and easy access for servicing with floor mounted cables relocated in raceways within the floor panels or under the floor boards.
The passenger cabins of aircraft are intended to provide maximum safety and comfort for passengers. An increasingly important component is the provision of passenger entertainment systems, mobile telephone services, laptop power and computer communications connectivity. Passengers are normally required to remain seated for extended periods and for optimum safety, the passengers should remain seated with safety belt fastened during a flight. To improve service, airlines plan to provide audio and video entertainment, telephone, intercom, television, video games, internet, email and electrical power supply for laptop computers, especially in business class and first class areas to permit passengers to work during the flight, communicate or seek entertainment.
The airlines have responded to passenger""s expectations and attempted to improve passenger service by providing such entertainment and communication services in existing aircraft and in new aircraft as they are purchased. Due to the confines of existing aircraft cabins and seating arrangements, it has been considered necessary to fit passenger seat units with entertainment and communication system electrical boxes or other passenger systems electrical boxes that are currently mounted to the seat legs under the seat. A conventional aircraft passenger seat is supported in single, two to five multiple seat units on a metal frame with legs that are secured within a seat track that can be adjusted for different seating pitch dimensions. Beneath the passenger seat, the area provided for carry on luggage has been reduced by the installation of passenger entertainment and communication system electrical boxes and other system""s boxes. Conventional system electrical boxes are approximately the size of a shoe box and can usually serve up to three separate passenger seats from a single unit located under one of the seats within the area originally provided for carry-on hand luggage.
The conventional location of these bulky digital system electrical boxes or other system""s boxes in the under seat hand luggage area has several disadvantages. Apart from reducing the area within the passenger cabin for hand luggage and the passenger""s feet, the installation of electrical equipment near passengers subjects the passenger to a risk of injury and potential electrical shock, as well as exposing the electrical equipment to potential accidental impact damage, vandalism, foreign matter ingestion into cooling fans and spilled beverages served within the passenger cabin. Since many such boxes are powered by 115 volt power, the risk of electrical shock or fire is significant. The electrical boxes interfere with cleaning of the passenger cabin and electronic units are exposed to potential damage from vacuum cleaners and cleaning solvents used during the cleaning of carpets and passenger seats.
The conventional location under the passenger seats also prevents the reduction in the quantity of such boxes that are required per aircraft. The location limits the size of boxes and routing of cables to multiple seats from a single box. In practical terms, conventional placement of boxes under passenger seats has limited the number of seats that can be served by a single box to three since a larger boxes would be needed for serving four or more seats.
The conventional under seat location also makes maintenance and inspection very difficult. For example, replacing an under seat system electrical box takes approximately one hour due to its inconvenient location. All electrical equipment generates heat and in order to extend the duty service life of electrical equipment, temperature control and air cooling is generally preferred. However, when electrical equipment is located under the seat of a passenger cabin, use of cooling fans is disadvantageous due to the noise level generated and risk of accidental contact. In addition, close proximity to a floor in a high traffic area with carpets and upholstery generates significant amounts of lint and dust that is sucked into air cooled electrical equipment by fans thereby requiring frequent cleaning. Often, cleaning does not occur and the electrical units become clogged with dirt and lint, overheat and fail. Despite the risks and added noise, typically small cooling fans are provided but under seat electrical components remain inadequately protected from damage and are poorly cooled with dusty air resulting in a significantly decreased service life.
Reduction in the exposure to potential damage, provision of adequate cooling and reduction of the number of boxes can result in significant savings for airline operators. For example, since many electronic entertainment unit boxes can cost up to $10,000 US each, and wide bodied aircraft may require over 100 units, the potential for savings in reducing the number purchased and improved maintenance are obvious.
Therefore, at best the current configuration of system electrical boxes in aircraft passenger cabins is a make shift attempt to provide an increased level of passenger services at minimum cost and minimal disruption to the passenger cabin environment. However, as a long-term solution, the provision of relatively large electrical boxes under the seats of passenger cabins suffers from several disadvantages. As demand for increased passenger entertainment, communication and work related services appears inevitable, the number and complexity of such passenger service electronics boxes will increase dramatically.
It is an object of the present invention to rationalize the configuration of passenger service electronics within the passenger cabin and stow such electrical components safely in an isolated environment away from all accidental and intentional interference from the passenger, carry-on luggage, as well as food and beverages served within the cabin.
It is a further object of the invention to provide adequate temperate control and cooling for the passenger seat electronic boxes within a clean controlled environment to extend the duty service life of electrical components.
It is a further object of the invention to minimize the expense and down time required to modify existing aircraft equipment by retrofitting existing airlines cabins and relocating existing passenger electronic components without requiring extensive modification to the aircraft or requiring the aircraft to be out of service for extended periods of time.
It is a further object of the invention to provide temperature control and monitoring for passenger seat electronic boxes utilising the existing passenger cabin air circulation and air conditioning system without requiring the expense and added weight of a separate dedicated cooling system.
It is a further object of the invention to enable use of larger electrical service boxes capable of serving a higher number of passenger seats, thus reducing the quantity of boxes needed per aircraft and reducing the total electrical power draw.
It is a further object of the invention to integrate power cables, and other cables into hidden raceways within floor panels or suspended under the removable floor panels of the passenger cabin floor.
Further objects of the invention will be apparent from review of the disclosure, drawings and description of the invention below.
The invention provides an under floor housing system for a passenger seat electronic units within an aircraft, where the aircraft typically includes a passenger cabin with a floor supporting the passenger seats and includes an air circulation system, temperature monitoring system, cooling fan rotation monitoring system and floor boards with integral cable raceways.
Conventionally such electronic units are shoebox sized metal boxes hung under the passenger seats where the location exposes electronics to damage, occupies valuable cabin space, and complicates access for servicing. The individual passenger seat electronic units are connected to a master control and units communicate via individual cables to a passenger interface accessible from an associated passenger seat. The units and interface are currently capable of or will soon be adapted for providing passenger services such as: audio entertainment; video entertainment; telephone; intercom; television; video games; internet access; email; and electrical power supply for laptop computers.
The under floor housing system has several individual housings, adjacent to the passenger seats, recessed beneath the floor surface level and above the cargo hold fire liner. Each housing has a removable top cover, side walls, and a bottom wall defining an interior compartment. A forced air cooling fan with temperature sensor and fan rotation sensor is provided for cooling each electronic unit within the interior compartment of each housing with an intake and outlet in communication with the passenger cabin air circulation system.
By providing a separate recessed housing beneath the floor surface, numerous advantages over the conventional under seat location for electronic passenger units are achieved.
The service life of electronic units is increased dramatically due to the control of temperature during operation. The cooling fans operate in conjunction with the air circulation flow within the fuselage which generally draws air from the passenger cabin to exit the cabin through louvers in the cabin side walls adjacent the floor and then proceeds in the lower lobe of the fuselage to vent about 50% and recirculate the remaining 50% with fresh compressed air from the engine compressors. Therefore the positioning of recessed housings, with air cooling fans under the floor, draws in spent air that has exited the cabin and does not increase the heat input into the cabin. As well, the air cooled under floor housings do not require a dedicated air supply nor separate air coolers since the air conditioning system of the cabin has sufficient capacity and directs air flow to the under floor area of the fuselage.
By clustering existing electronic units within the under floor recessed housing, the electronic units are more easily accessible for service, inspection and replacement by maintenance personnel. For example, in an under seat location replacement of a defective unit requires approximately one hour of maintenance personnel time whereas the increased accessibility and visibility of cluster units in the recessed under floor housing makes replacement of a defective unit a simple matter of releasing the defective unit from the housing and reconnecting within five to ten minutes. The under floor housing includes a positive latch and mounting brackets that permit quick release of the electronic units for servicing and a sure and positive electrical connection when installed. The risk of electrical arcing from improper installation or disengagement during vibration is eliminated by the positive and sure connection within the recessed housing. The enclosure of units within the housing with a secure locked top cover reduces the danger to passengers.
Compared with the conventional under seat location, the recessed under floor housing conserves valuable passenger cabin space for carry-on luggage and eliminates dangerous exposed wiring. The cabin area remains available for passenger needs and is less cluttered for security inspections, cleaning and maintenance. As well, passengers and electric powered components are separated thereby reducing the risk of passenger injury and damage to the equipment from passengers, their luggage or food and beverages served in the passenger cabin. Intentional vandalism by passengers is eliminated by hiding the electrical units in the under floor housing.
A significant advantage of the invention is the ability to relocate or retrofit existing electronic components in existing aircraft. The units can be removed from their current location under seats and relocated in an under floor cluster within the housing. No changes need to be introduced in the functional capabilities of existing electronic components. The cabling from master control to each unit in the housing and cabling from the units to the passenger seats is reinstalled due to the different lengths and configuration of cables.
Increased control over the temperature of the electrical system operation is provided by positive airflow through the under floor housings and temperature sensors. The sensors alert the cabin crew through displays on a control panel in the event of any malfunction.
Airlines can more easily add electronically delivered passenger services to relatively crowded economy sections of the cabin with far less units since bulky electronic components can be stored in the under floor air cooled housings rather than in conventional under seat locations. Economy cabins have less space available for storing additional electronics boxes under the seats that would create a lack of space for passenger""s feet and carry on luggage.
A further less obvious advantage however is the ability to easily upgrade passenger electronic units by replacing existing system electrical boxes in existing aircraft as the technology evolves and passenger services increase. For example, currently four seat passenger seating arrays are served by two system electrical boxes since current system electrical boxes are only capable of serving one to three separate passenger seats. By clustering the passenger electronics in an under floor housing, new higher capacity equipment can be provided sufficient to serve four or more seats if desired, without much concern over the additional size of the new equipment since it is stored under the floor. Further in the future, the existing cluster of three or four separate system electrical boxes may be replaced by a rationalized system that uses a single power supply resulting in a much smaller combined unit and lower power draw. Further in the future, it may be possible to provide an entirely new electronic system, which includes its own power supply and modern board with PC card to serve twelve or more seats from a single unit. The improved access for maintenance and servicing in housings under the floor, and grouping of units in clusters will make future upgrades easier, less costly in terms of the quantity of units and quicker to implement thus reducing labour costs and downtime. An aircraft that is out of service for maintenance or equipment upgrading, is not earning revenue and a quick turnaround is critical in implementing any such system upgrade.
In addition, since it is necessary in a retrofit to remove and replace several floor panels, the invention can easily provide for a recessed cable raceway in floor panels or an under floor suspended raceway adjacent to the seat tracks to route conduits and cables to individual seats in a raceway. The advantage of an under floor or recessed raceway is that existing plastic seat track cover strips can be eliminated and the entire cabin floor can be provided with a flat flush carpeted surface. Existing seat track cover strips enclose cables beneath them and rise above the carpeted floor level as a result. Plastic seat track covers are sometimes referred to as xe2x80x9cspeed bumpsxe2x80x9d due to their appearance and impedance of pedestrian traffic. Use of a recessed cable raceway and flush carpeted floor over the cables and seat track removes a tripping hazard, simplifies cleaning of the floor surface, reduces maintenance of the floor surface and improves the visual appeal of the passenger cabin.